scholarly journals On gyration radius distributions of star-like macromolecules

2021 ◽  
Vol 2021 (6) ◽  
pp. 063213
Author(s):  
Yury A Budkov ◽  
Andrei L Kolesnikov
Keyword(s):  
Gyration Radius

Interpretation of Preferential Adsorption Using Random Phase Approximation Theory

1995 ◽  
Vol 60 (10) ◽  
pp. 1641-1652 ◽  
Author(s):  
Henri C. Benoît ◽  
Claude Strazielle
Keyword(s):  
Approximation Theory ◽  
Random Phase Approximation ◽  
Virial Coefficient ◽  
Random Phase ◽  
Second Virial Coefficient ◽  
Solvent Mixture ◽  
Gyration Radius ◽  
Thermodynamic Quantities ◽  
Phase Approximation ◽  
Preferential Adsorption

It has been shown that in light scattering experiments with polymers replacement of a solvent by a solvent mixture causes problems due to preferential adsorption of one of the solvents. The present paper extends this theory to be applicable to any angle of observation and any concentration by using the random phase approximation theory proposed by de Gennes. The corresponding formulas provide expressions for molecular weight, gyration radius, and the second virial coefficient, which enables measurements of these quantities provided enough information on molecular and thermodynamic quantities is available.

scholarly journals Loading and Release of Anti -Cancer Drugs Using Simultaneous pH and Temperature Responsive Nanohybrid

2020 ◽  
Author(s):  
Reza Maleki ◽  
Mohammad Dahri ◽  
Hossein Akbarialiabad
Keyword(s):  
Anticancer Drugs ◽  
Anticancer Agents ◽  
Drug Carrier ◽  
Drug Loading ◽  
Dynamics Simulation ◽  
Gyration Radius ◽  
Neoplastic Tissue ◽  
Trimethyl Chitosan ◽  
Dual Responsive ◽  
Adsorption And Release

Abstract BackgroundTodays, drug nanocarrier development and improving its biophysical properties is one of the updated and intended of nano-biopharmaceutical science researches. Single-walled carbon nanotubes (SWCNT), as a typical carbon structure based nanocarrier, but have some obstacles in drug delivery mechanisms. In that current study, the penetration, loading, and release of Doxorubicin and Paclitaxel, as two anticancer agents, were investigated using a novel modified and functionalized SWCNT.ResultsThis study was carried out using molecular dynamics simulation based on a dual-responsive smart biomaterial. At the in-silico study, Interaction energies between drugs and carriers, numbers of hydrogen bonds, diffusion coefficient, and gyration radius were investigated. The kinetic analysis of drug adsorption and release revealed that, fascinatingly, drug loading and drug release are selective at physiological and cancerous acidic pH, respectively. Interaction of Dimethyl acryl amid-trimethyl chitosan, as a biodegradable and biocompatible hydrogel, with SWCNT indicated that degradation reaction in acidic condition destructs the polymer, which leads to a smart release in cancerous tissue at specific pH. Moreover, it resolves hydrophilicity, optimum nanoparticle size, cell membrane penetration, and cell toxicity concerns.ConclusionsThe simulation results indicated a marvelous role of dimethyl acryl amide-trimethyl chitosan in the adsorption and release of anticancer drugs in normal and neoplastic tissue. The interaction of trimethyl chitosan also improves biocompatibility as well as biodegradability of the carrier. Overall, that novel drug carrier can be a virtuous nanoparticle for loading, transporting, and releasing the anticancer drugs.

scholarly journals Two Contact Binaries with Mass Ratios Close to the Minimum Mass Ratio

2021 ◽  
Vol 922 (2) ◽  
pp. 122
Author(s):  
Kai Li ◽  
Qi-Qi Xia ◽  
Chun-Hwey Kim ◽  
Shao-Ming Hu ◽  
Di-Fu Guo ◽  
...  
Keyword(s):  
Gyration Radius ◽  
Mass Ratio ◽  
Mass Ratios ◽  
Contact Binaries ◽  
Contact Binary ◽  
Low Mass ◽  
Ratio Limit ◽  
Low Mass Ratio ◽  
Diagram Analysis

Abstract The cutoff mass ratio is under debate for contact binaries. In this paper, we present the investigation of two contact binaries with mass ratios close to the low mass ratio limit. It is found that the mass ratios of VSX J082700.8+462850 (hereafter J082700) and 1SWASP J132829.37+555246.1 (hereafter J132829) are both less than 0.1 (q ∼ 0.055 for J082700 and q ∼ 0.089 for J132829). J082700 is a shallow contact binary with a contact degree of ∼19%, and J132829 is a deep contact system with a fill-out factor of ∼70%. The O − C diagram analysis indicated that the two systems manifested long-term period decreases. In addition, J082700 exhibits a cyclic modulation which is more likely resulting from the Applegate mechanism. In order to explore the properties of extremely low mass ratio contact binaries (ELMRCBs), we carried out a statistical analysis on contact binaries with mass ratios of q ≲ 0.1 and discovered that the values of J spin/J orb of three systems are greater than 1/3. Two possible explanations can interpret this phenomenon. One explanation is that some physical processes, unknown to date, are not considered when Hut presented the dynamic stability criterion. The other explanation is that the dimensionless gyration radius (k) should be smaller than the value we used (k 2 = 0.06). We also found that the formation of ELMRCBs possibly has two channels. The study of evolutionary states of ELMRCBs reveals that their evolutionary states are similar with those of normal W UMa contact binaries.

Optimizing tuned mass damper parameters to mitigate the torsional vibration of a suspension bridge under pulse-type ground motion: A sensitivity analysis

2019 ◽  
Vol 26 (11-12) ◽  
pp. 1054-1067 ◽  
Author(s):  
Seyyed Hossein Hossein Lavassani ◽  
Hamed Alizadeh ◽  
Peyman Homami
Keyword(s):  
Sensitivity Analysis ◽  
Torsional Vibration ◽  
Passive Control ◽  
Suspension Bridge ◽  
Tuned Mass Damper ◽  
Gyration Radius ◽  
Suspension Bridges ◽  
Torsional Mode ◽  
Mass Damper ◽  
Pulse Type

Suspension bridges are structures that because of their long span and high flexibility can be prone to ambient vibrations such as ground motions. They can experience high amplitude vibrations in torsional mode during an earthquake, where a vibration control strategy seems necessary. Recently, control systems have been widely used to mitigate vibration of structures. Tuned mass damper is a passive control system. Its performance and effectiveness have been verified both theoretically and practically. In this study, a tuned mass damper system is used to mitigate the torsional vibration of a suspension bridge. The Vincent Thomas suspension bridge is selected as a case study, and its response is reduced by a tuned mass damper under ten pulse-type records from 10 major worldwide earthquakes. By using sensitivity analysis, a parametric study is carried out to optimize tuned mass damper parameters, namely, mass ratio, gyration radius, tuning frequency, and damping ratio according to the maximum reduction of the response maxima. Finally, the optimum range of each parameter that can give the best performance and provide both operational and economic justification for the implementation of the project is suggested. The numerical results indicate that the optimized tuned mass damper system can substantially reduce the maximum response and vibration time.

scholarly journals Genetic and Environmental Factors Associated to Glutenin Polymer Characteristics of Wheat

Foods ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 683 ◽  
Author(s):  
Gérard Branlard ◽  
Annie Faye ◽  
Larbi Rhazi ◽  
Ayesha Tahir ◽  
Véronique Lesage ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Grain Protein Content ◽  
Gyration Radius ◽  
Molecular Characteristics ◽  
Climatic Data ◽  
Field Flow Fractionation ◽  
Factors Associated ◽  
Average Temperature ◽  
Genetic And Environmental Factors ◽  
Glutenin Polymer

The polymers of wheat glutenins are studied here using asymmetric flow field flow fractionation (A4F). Molecular mass (Mw), gyration radius (Rw), and the polydispersity index (PI) of polymers were measured over a four-year, multi-local wheat trial in France. The experiment, involving 11 locations and 192 cultivars, offered the opportunity to approach the genetic and environmental factors associated with the phenotypic values of the polymer characteristics. These characteristics, which were all highly influenced by environmental factors, exhibited low broad-sense heritability coefficients and were not influenced by grain protein content and grain hardness. The 31 alleles encoding the glutenin subunits explained only 17.1, 25.4, and 16.8% of the phenotypic values of Mw, Rw, and PI, respectively. The climatic data revealed that a 3.5 °C increase between locations of the daily average temperature, during the last month of the grain development, caused an increase of more than 189%, 242%, and 434% of the Mw, Rw, and PI, respectively. These findings have to be considered in regard to possible consequences of global warming and health concerns assigned to gluten. It is suggested that the molecular characteristics of glutenins be measured today, especially for research addressing non-celiac gluten sensitivity (NCGS).

Molecular dynamics simulation of aggregation of monocrystal and polycrystal copper nanoparticles

2019 ◽  
Vol 33 (16) ◽  
pp. 1950168
Author(s):  
Linxing Zhang ◽  
Guang Hong ◽  
Shouyin Cai
Keyword(s):  
Molecular Dynamics ◽  
Lattice Structure ◽  
Displacement Vector ◽  
Mean Square Displacement ◽  
Dynamics Simulation ◽  
Gyration Radius ◽  
Mean Square ◽  
Shrinkage Ratio ◽  
Lower Temperature ◽  
Dynamics Simulations

Molecular dynamics simulations were employed to investigate the aggregation of monocrystal and polycrystal nanoparticles. The lattice structure, displacement vector, potential energy, shrinkage ratio, relative gyration radius and mean square displacement of the two systems are compared. The results indicate that the aggregation of polycrystal nanoparticles is more drastic than that of monocrystal nanoparticles. Besides, the polycrystal nanoparticles are found contacted and melted at lower-temperature than that of monocrystal nanoparticles. The reason for all these phenomena is that there is additional surface energy in the grain boundary of polycrystal nanoparticles.

scholarly journals Van der Waals interactions between polymers with sequence-specific polarizabilities: Stiff polymers and Gaussian coils

2016 ◽  
Vol 31 (02n03) ◽  
pp. 1641035 ◽  
Author(s):  
Bing-Sui Lu ◽  
Ali Naji ◽  
Rudolf Podgornik
Keyword(s):  
Interaction Energy ◽  
Van Der Waals ◽  
Pairwise Interaction ◽  
Van Der Waals Interaction ◽  
Van Der Waals Interactions ◽  
Attractive Interaction ◽  
Gyration Radius ◽  
Interaction Energies ◽  
Anisotropic Interaction ◽  
Decay Behavior

We consider the van der Waals interaction between a pair of polymers with quenched heterogeneous sequences of local polarizabilities along their backbones, and study the effective pairwise interaction energy for both stiff polymers and flexible Gaussian coils. In particular, we focus on the cases where the pair of polarizability sequences are (i) distinct and (ii) identical. We find that the pairwise interaction energies of distinct and identical Gaussian coils are both isotropic and exhibit the same decay behavior for separations larger than their gyration radius, in contradistinction to the orientationally anisotropic interaction energies of distinct and identical stiff polymers. For both Gaussian coils and stiff polymers, the attractive interaction between identical polymers is enhanced if the polarizability sequence is more heterogeneous.

Quantitative Evaluation of the Uniformity of Abrasive Distribution Based on Image Processing

2010 ◽  
Vol 135 ◽  
pp. 314-318
Author(s):  
Bing Suo Pan ◽  
Biao Wan ◽  
Xiao Hong Fang
Keyword(s):  
Image Processing ◽  
Fractal Dimension ◽  
Voronoi Cell ◽  
Precision Machining ◽  
Gyration Radius ◽  
Local Distribution ◽  
Face Images ◽  
Working Face ◽  
Mean Crowding ◽  
Points Of View

In precision machining, the uniformity degree of abrasive distribution affects significantly the surface quality. To quantitatively evaluate the uniformity of abrasive distribution, in this paper digital image processing technology was employed to segment the working face images of impregnated diamond tools; mean crowding index was used to classify the pattern of abrasive distribution; fractal dimension determined by gyration radius method was applied to characterize the bulk uniformity of abrasive distribution on face plane; the coefficient of variation of Voronoi cell areas was adopted to describe the local distribution feature of abrasive grits. The results show that mean crowding index, fractal dimension and CV of Voronoi cell areas can characterize the uniformity of abrasive distribution from different points of view, and can be used to quantitatively evaluate the uniformity of abrasive distribution.

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